Either ' or " delimited; length limit is 2,097,151 on YMP or
16,384 characters on other machines.

CF90

Either ' or " delimited.

DEC F77

Either ' or " delimited; C backslash escapes (\n,etc.)
accepted.

DEC F90

Either ' or " delimited; C backslash escapes (\n,etc.) not
normally accepted. If string is followed immediately by C
then backslash escapes are accepted and the string is NULL
terminated. Length must be in the range 0 to 2000.

PGF77

Either ' or " delimited; C backslash escapes (\n,etc.)
accepted.

Sun F77

Either ' or " delimited; length limit is 65,535; C backslash
escapes (\n,etc.) accepted; If not in a data statement, then
followed by a null; zero length character constants are
allowed only as actual arguments.

Sun F90

Either ' or " delimited; length limit is 65,535; C backslash
escapes (\n,etc.) accepted; If not in a data statement, then
followed by a null.

character set

characters available for use in source text

Fortran 77

Always case insensitive except in character strings.

Fortran 90

Always case insensitive except in character strings.

IBM XLF

Case sensitive if -U is specified.

CIVIC

Always case insensitive except in character strings.

CF77

Case insensitive except in character strings.

CF90

Case insensitive except in character strings.

DEC F77

Case sensitive if -names as_is or -U is used; external
names are forced to upper case if -names uppercase is given.

DEC F90

Case sensitive if -names as_is is used; external names are
forced to upper case if -names uppercase is given.

In fixed form, any character other than a blank or a zero in
column 6 indicates a continuation line.

Fortran 90

In free form input, an & at the end of a line indicates that
the next non-comment line is a continuation line. If the
first character on that continuation line is an & then the
statement continues after that &; otherwise it continues with
column 1 of the continuation line.

IBM XLF

6700 characters are allowed in a statement, spread out over
any number of continuation lines. No tab convention in
fixed-form input is provided. Free form input is the same as
Fortran 90.

CIVIC

A statement label starting before column 6 may include a
character in column 6. An & at the end of a line indicates
that the next non-comment line is a continuation line.

CF77

Tab in columns 1-5 followed by non-zero digit taken as
continuation with digit in column 6. Up to 99 continuation
lines allowed.

CF90

Tab in columns 1-5 followed by non-zero digit taken as
continuation with digit in column 6 in fixed form. Up to 99
continuation lines allowed in fixed form, 59 in free form.

DEC F77

Tab in columns 1-5 followed by non-zero digit taken as
continuation with digit in column 6. Up to 99 continuation
lines allowed.

DEC F90

In fixed form, tab in columns 1-5 followed by non-zero digit
taken as continuation with digit in column 6. Up to 511
continuation lines allowed.

PGF77

& in column 1 or non-zero digit in column 6 or after initial
tab; Up to 99 continuation lines allowed.

Sun F77

& in column 1 or non-zero digit after first tab if initial
line starts with tab in 1-6. Up to 99 continuation lines
allowed by default-- the -Nlk option can be used to change
the number of continuation lines allowed to k.

Sun F90

non-zero digit after first tab if initial line starts with tab
in 1-6. Up to 99 continuation lines allowed by default

file names

length of file names (per link in path and entire path)

IBM XLF

255 characters in link; 1023 characters in path.

CIVIC

16 characters in link; 255 characters in path on NLTSS 255
characters in link; 1024 characters in path on UNICOS.

CF77

256 characters in link; 1023 characters in path.

CF90

256 characters in link; 1023 characters in path.

Sun F77

512 characters in link; 1024 characters in path.

Sun F90

512 characters in link; 1024 characters in path.

Hexadecimal constants

forms of base 16 constants

Allowed representations of the hexadecimal numbers 05AF and
-0fAF are shown here:

Fortran 77

Not available.

Fortran 90

Z'05af' or Z"05af" only in data statements.

IBM XLF

Z'05af' or Z"05af" or '05af'Z or "05af"Z or X'05af' or
X"05af" or '05af'X or "05af"X are allowed in any expression.
Z05af is allowed only in data statements.

CIVIC

#05af

CF77

X'05af' or X"05af" or X'-05af' or X"-05af"

CF90

X'05af' or X"05af" or X'-05af' or X"-05af" or Z'05af' or
Z"05af" allowed anywhere and treated as typeless.

DEC F77

Z'05af' or Z"05af" or '05af'Z or "05af"Z or X'05af' or
X"05af" or '05af'X or "05af"X

DEC F90

Z'05af' or Z"05af" or '05af'X or "05af"X

PGF77

z'05af' or Z'05af' or '05af'x or '05af'X (single quotes
only; up to 64 bits).

Sun F77

z'05af' or x'05af' or '05af'x or '05af'z

Sun F90

Z'05af' or Z"05af" or x'05af' or x"05af" can be used anywhere
and are treated as a typeless. Up to 8 hex digits are
allowed.

Hollerith constants

forms of Hollerith and related character constants

Allowed representations of the Hollerith constants are shown
here (including some forms that give left or right
justification and blank or null fill):

Fortran 77

2Hab

Fortran 90

Not available.

IBM XLF

2Hab with a maximum count of 255.

CIVIC

2Hab 2Rab 2Lab

CF77

2Hab 'ab'H "ab"H 2Rab 'ab'R "ab"R 2Lab 'ab'L "ab"L

CF90

2Hab 'ab'H "ab"H 2Rab 'ab'R "ab"R 2Lab 'ab'L "ab"L

DEC F77

2Hab

DEC F90

2Hab with a maximum count of 2000.

PGF77

2Hab can be used as arithmetic constant but not as
characer constant; maximum count is 2000.

Allowed range is -2**63 to 2**63-1; the kind is promoted as
necessary to be of a kind large enough to contain the
constant.

CIVIC

Allowed range is -2**63 to 2**63-1.

CF77

Default range is -2**45 to 2**45-1.

CF90

Default range is -2**46 to 2**46-1.

DEC F77

Allowed range is -2**63 to 2**63-1.

DEC F90

Allowed range is -2**63 to 2**63-1 for kind=8.

PGF77

Allowed range is -2147483648 to 2147483647 (-2**31 to 2**31-1
inclusive).

Sun F77

Allowed range is -2147483648 to 2147483647 (-2**31 to 2**31-1
inclusive) unless the -dbl option is set (in which case the
range is -2**63 to 2**63-1).

Sun F77

Allowed range is -2147483648 to 2147483647 (-2**31 to 2**31-1
inclusive)

label

statement label

A label is one to five digits in columns 1 to 5. At least
one digit must be non-zero.

Fortran 90

A label may start in any column if all preceeding columns on
the line are blank.

CIVIC

Alphanumeric labels are allowed. Label starts in columns 1-5
but may extend beyond column 5. A colon (:) may be used
after a label to separate it from the statement.

logical constants

forms of logical constants

Fortran 77

.false. and .true.

Fortran 90

.false. and .true.

IBM XLF

.false. (0) and .true. (1)

CIVIC

.false. (0) and .true. (1)

CF77

.false. (0) and .true. (-1) on XMP/YMP or .t. and .f.

CF90

.false. (0) and .true. (-1) or .t. and .f.

DEC F77

.false. (0) and .true. (-1)

DEC F90

.false. (0) and .true. (-1); can use integers as logicals.

PGF77

.false. (0) and .true. (-1) or any with low-order bit set
taken as .true.; can use logicals as integers and integers as
logicals; Can use T and F in data statements and in
namelist input; with -Munixlogical .true. is 1 and any
non-zero is taken as .true.

Sun F77

.false. (0) and .true. (1) or any non-zero taken as
.true.; can use logicals as integers and integers as
logicals.

In Fixed Form, F77 plus: Trailing comments with !
Multiple statements per line with ; seperator.

In Free Form:
Each line is up to 132 characters long;
Blanks are significant;
Trailing comments with !
Multiple statements per line with ; seperator;
Label must be followed by blank (and still maximum of 5
digits);
Continuation by putting & at end of line to continue (and
also possibly at start of next line).

IBM XLF

In Fixed Form, F77 plus:
Trailing comments with ! (except in column 6);
Multiple statements per line with ; seperator;
Tab in columns 1 to 6 means that column 7 follows tab--label
can't follow tab;
Any character in column 6 (including ! or ;) other than zero
or blank indicates continuation.

In Free Form,
Same as Fortran 90 except that any number of columns are
allowed on a line.

In IBM Free Form: Comment is " (double quote) in column 1 or
! in any column;
Blanks are not significant;
- (minus sign) at end of a line (or before trailing comment)
means next line is a continuation line (although there is no
indication on the continuation line itself). Maximum
statement length is 6700 characters.

CIVIC

Label may go beyond column 5;
Number of columns is settable on execute line;
Continuation can be by & at end of line to be continued;
$ in column 1 may be used for commend;
Multiple statements per line by using $ (but not ; )
Trailing comments with ! or $$c, etc.

CF77

Same as F77 except as follows: Tab in columns 1 to 5
followed by non-zero digit is continuation;
Tab in columns 1 to 5 followed by letter is initial line;
Trailing comments with ! Number of columns may be increased
to 80 with -N80 option.

CF90

Same as F90 except as follows in fixed form:
Tab in columns 1 to 5 followed by non-zero digit is
continuation;
Tab in columns 1 to 5 followed by letter is initial line;
Trailing comments with ! Number of columns may be increased
with -N80 or -N132 option.

DEC F77

Same as F77 except as follows:
Tab in columns 1 to 5 followed by non-zero digit is
continuation;
Tab in columns 1 to 5 followed by letter is initial line;
Trailing comments with !

DEC F90

In Fixed Form, F77 plus:
Trailing comments with ! (except in column 6);
Multiple statements per line with ; seperator;
Tab in columns 1 to 6 means that column 7 follows tab--label
can't follow tab;
Up to 511 continuation lines are allowed. Any character in
column 6 (including ! or ;) other than zero or blank
indicates continuation.

In Free Form, F90 plus:
Up to 511 continuation lines are allowed.

PGF77

Same as F77 except as follows:
Tab in columns 1 to 5 followed by non-zero digit is
continuation;
Tab in columns 1 to 5 followed by letter is initial line;
Trailing comments with !

Sun F77

Same as F77 except as follows:
Tab in columns 1 to 5 followed by non-zero digit is
continuation;
Tab in columns 1 to 5 followed by letter is initial line;
Trailing comments with !.

Sun F90

In Fixed Form, F77 plus:
Tab in columns 1 to 5 followed by non-zero digit is
continuation;
Tab in columns 1 to 5 followed by letter is initial line;
Trailing comments with !. Up to 99 continuation lines are
allowed.
In Free Form: Up to 99 continuation lines are allowed.